Lazy loading for opusfilter

filters/opusfilter/opusfilter-ersatz.py

@@ -3,15 +3,29 @@
 import os
 
 # Prevent searching for modules in the filters/ directory (like langid)
-sys.path.remove(os.getcwd())
+del sys.path[0]
 
 import importlib
+import importlib.util
 import yaml
 import itertools
 import argparse
 import logging
 import warnings
 
+def lazy_import(name):
+	spec = importlib.util.find_spec(name)
+	if not spec:
+		raise ImportError(name)
+	loader = importlib.util.LazyLoader(spec.loader)
+	spec.loader = loader
+	module = importlib.util.module_from_spec(spec)
+	sys.modules[name] = module
+	loader.exec_module(module)
+	return module
+
+opusfilter = lazy_import('opusfilter')
+
 parser = argparse.ArgumentParser()
 parser.add_argument('--quiet', '-q', action='store_true')
 parser.add_argument('filter', type=str)
@@ -28,9 +42,6 @@
 	# BeautifulSoup (the HtmlTagFilter)
 	warnings.filterwarnings('ignore', module='bs4')
 
-# Delayed loading opusfilter to install warning filter
-import opusfilter
-
 module_path, class_name = args.filter.rsplit('.', maxsplit=1)
 
 config = yaml.safe_load(args.config)